Coating formulations find use in various industries including the coating and/or painting of motor vehicles. In these industries, and in the automotive industry in particular, considerable efforts have been expended to develop coating compositions with improved performance properties. In the automotive industry, for example, numerous approaches have been advanced to achieve improved chip resistance and corrosion protection. These efforts have included, for example, applying up to 6 or more individually applied coating layers over the substrate by one or more coating methods.
Such efforts have resulted in increased protection of the surface of the substrate and reduced paint loss through chipping when the substrate of the vehicle is hit with solid debris such as gravel and stones. For example, it has been found that reducing the difference in impact energy between multiple coating layers may improve the chip resistance of the overall coating system, especially for coatings in which the respective coating layers have excessive differences in hardness. It is believed that reducing the hardness differential can lessen delamination between the coating layers such as between the undercoat, an intermediate coat, and a top coat or an undercoat and an intermediate coat.
Significant time and effort have been expended to develop effective chip resistant coating system applications, such as through various coating formulations and/or intermediate coating layers that have been employed to increase the chip resistance in the finished product. It has also been a goal of automakers to develop more compact coating systems at assembly plants through the elimination of one or more coating layers, without adversely impacting chip resistant properties that, in many instances, is a competing interest in developing coating layers that provide good chip resistance. Elimination of coating layers provides time and cost benefits that are important to the efficiency of the overall coating process. The anti-chip primer layer, applied prior to the primer surfacer, is one coating layer that automakers have targeted for elimination. However, obtaining chip resistant properties of composite coating layers employing primer surfacer/basecoat/clearcoat or primer surfacer/monocoat systems over substrates that are difficult to coat, such as zinc coated metals, is difficult to achieve without the application of an antichip primer layer.
Accordingly, the need exists for a material that may be used in coating systems that may eliminate the need for certain coating layers, such as the antichip primer layer, while also providing chip resistant properties that are comparable to existing coating systems.